This invention relates to stents for maintaining flow through arterial vasculature while serving as drug delivery vehicles. The invention has particular reference to stents comprising compounds useful for the treatment and prevention of restenosis, increase in cell surface antithrombotic activity, and reduced inflammatory responses from the body of the patient receiving the stent.
Commonly used methods of treating cardiovascular disease includes angioplasty or atherectomy. While these methods are successful in relieving the symptoms of cardiovascular disease, the procedure produces a high rate of arterial re-closure or restenosis. Various methods of preventing restenosis have been tested, however, these methods have met with varying degrees of success.
Since restenosis can begin immediately after the angioplasty or atherectomy procedure and can continue for months post procedure, it is desirable to provide a device and method capable of providing the sustained delivery of a medicating composition to inhibit restenosis and to reduce the inflammatory response and effect, including an increase in cell surface anti-thrombotic activity of the endothelium.
An acceptable method of sustained long term drug delivery employs metal stents coated with a bioabsorbable synthetic polymer that have also been used to deliver medicament. However, most such metal stents are thrombogenic and being a “foreign body” stimulates the host's inflammatory response.
Preferably, such a stent should be minimally inflammatory, non-thromboginic, biologically compatible and capable of sustained drug delivery to the endothelium and provide for increased cell surface antithrombotic effect without increasing the risk of the patient becoming a “bleeder” or to be at appreciably increased risk of hemorrhaging either due to internal or external injury.